In Australia 'abduct' is far more common than 'kidnap'. And particularly when it comes to children being illegally taken when a couple are separated/divorced, you almost never hear or read the term 'kidnap'. 'Abduct' is always the term used.

Thank you, Angelina and Jaque! From the legal point of view, they are the same. That’s good to know, thanks!

abduct and kidnap are synonyms of one another, and so can be used interchangeably. Both terms refer to the unlawful detention of a person against their will. Interestingly, they are the same even in the eyes of the law itself.

I am a english speaker from california and I think that these two words are basically the same as far as usage goes. Perhaps, abduct is more formal.